Hydraulic retarder control



July 26, 1960 J. B. sNoY 2,946,416

HYDRAULIC RETARDER CONTROL Filed Jan. 7, 1959 COOLER United States HYDRAULIC RETARDER CGNTROL Joseph B. Snoy, Rockford, lll., assignor to Borg-Warner Corporation, Chicago, lll., a corporation of Illinois Filed Jan. 7, 1959, Ser. No. 785,459

11 Claims. (Cl. 192-4) This invention relates to hydraulic retarders and more particularly to a control for a hydraulic retarder intended for use in braking vehicles equipped with automatic transmissions.

Heretofore, hydraulic retarders have been proposed which utilized hydraulic uid from the automatic transmissions in a chamber having xed and rotatable vanes for vehicle braking. These devices commonly have a fluid cooler in series with the retarder so that in the event that the fluid flowing to the retarder is throttled, the iluid flowing through the cooler is also throttled. The disadvantages of this arrangement are apparent; in devices of this type the amount of lill cannot be eectively thtrottled because of the excessive heat developed in the oil being circulated. As a result, these retarders have to be operated only when the retarder iscompletely full.

A primary object of the invention is, therefore, to provide a control for a hydraulic retarder wherein the lill Y of the retarder may be accurately controlled for any predetermined degree of braking from minimum to maximum.

A further object of the invention is to provide a hydraulic retarder control in which the retarder and the cooler are in a closed loop system to afford constant cooling of the hydraulic huid during braking.

Another object of the invention is to provide a hydraulic retarder of the stated type wherein the hydraulic liuid is circulated during braking by the pressure head developed by the impeller of the retarder.

A further object of the invention is to provide a hy- Idraulic retarder in accordance with the preceding objects in which the amount of braking varies in accordance with the degree of iilling of a closed loop system.

Another object of the invention is to provide a hydraulic retarder of the mentioned character having a valve which is manually actuatable to a lill position which may be maintained for a predetermined period of time to aiiord a predetermined degree of braking.

This invention consists of the novel constructions, arrangements, and Vdevices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will be apparent from the following description of preferred forms ofthe invention, illustrated with reference to the accompanying drawings, wherein the sole ligure of the drawing is a schematic Viewof a retarder control system made in accordance with the present invention and shown in conjunction with a schematic representation of portions of a hydraulic transmission system.

Referring to the drawing, reference numeral l indi- Vcates the vehicle brake system of the present invention to a rear pump of the automatic transmission, through 2,945,416 Patented July 26, 1960 2 a main regulating valve 24, which in the presen-t instance, regulates the pressure to the conventional hydraulic clutches of the transmission by way of conduit 26 to approximately p.s.i. The pumps Z0 and 22 are shown as arranged in parallel relation, the pump 22 being adapted to `supply iluid for the transmission when push-starting and the pump 20 being adapted to supply fluid pressure to the transmission when the vehicle engine is operating. In the latter event, the output of the pump 22 is bypassed to sump by a valve 23. It will be appreciated that the disclosure of the present vehicle braking system is illustrative only and that this system may be entirely separate from a hydraulic transmission so `long as means are provided to pressurize the uid.

The main regulating Valve 24 includes a slidable plunger 25 biased to the left, as viewed in the drawing, by means of a spring 27. The plunger 25 has a spindle 29 maintaining lands 31 and 33 in spaced relation. A bleed hole 35 is formed in the land 31 to permit the ilow of fluid from the area surrounding the spindle Z9 to the left side of the land 31. When the fluid pressure onthe left side of the land 31 exceeds a predetermined value the plunger 25- is urged to the right, as viewed in the drawing, against the force of the spring 27. In this instance, liuid may be discharged from the valve 24 through a conduit 28 so that the fluid pressure between the pumps 20 and 22 on the valve 24 is maintained at approximately 110 p.s.i.

Fluid is supplied to the converter 11 through the conduit 28 and a conduit 39 at a pressure of approximately 8O p.s.i. This pressure is maintained by a pressure regulating valve 38, the operation of which is similar to that of valve 24 and need not be described in detail. The hydraulic fluid, during the normal operation of the transmission, normally liows from the converter 11 to a cooler 34, which is preferably of the secondary heat exchange type and desirably utilizes the vehicle engineV cooler as a primary iluid. This iluid flows to the cooler 34 by means of a conduit 32 and returns to the converter sump 13 by means of a conduit 36. As is hereafter apparent, the cooler 34is utilized to cool the iluid from the converter 11 only during normal operation of the vehicle.

Positioned between the sump 1S and the regulating valve 38 -is a regulating valve 40 set to maintain the pressure of oil in lubricant line 42 at approximately l0 p.s.i. Fluid in excess of that required to maintain the respective pressure flows back to sump in conventional manner. The operation of the valve 40 is similar to that of the valves 24 Aand 38 and will not be further described.

According to the present invention a hydraulic retarder 44 is connected to a driven shaft 46 and liuid is selectively received through it from the converter 11 through the medium of a control valve 48 which is movable by means of a suitable pedal (not shown) to the lill position. This control valve 48 may then be retracted to the hold position to terminate communication between the converter 11 and the cooler 34 while the retarder 44 is in operation. In addition, as will be apparent, the valve 48 sequesters a portion of the fluid in a closed loop system between the retarder 44 and the cooler 3.4.- It will be obvious that the valve 48 need not be throttled as is required of control valves ,of heretofore known retarders. As a result, the desired degree of retardation is always readily obtainable.

The retarder 44 is shown as including a fixed varied reaction plate Si) in closed coupling relation to a rotatable vaned impeller 52 connected to the shaft 46. -The kinetic energy of the shaft 46 is converted to heat in the liuid in the retarder 44 and the heat is dissipated by the cooler 34 as will be apparent.

The control valve 48 is shown as including a casing 54 having a central bore 56 and provided with an end plate 58 having a bore 59 slightly exceeding the bore 56 in diameter and dening a shoulder 60. An end cap 61, hereinafter described in detail is secured by any suitable means ,to .the-plate. 5S and thefcasing 54. .fSlidablyreceived 1withinhe bore-56,is aplungerfZ .havingt at-.one .end. a ibase ,section ,64.provided withgan .ear or ,lug-T66 Ftor.,connection-by a-.siiitable link` onthe like tolt-hepedal desirably positioned near a foot of .thewvehicle .operator. Lhefplunger 62 further includes-,a central:; spindle-63, ,spaced `controllands .68, `70v and 72-and a.bas`esection 73,:atthe opposite, end. Pr'eferablythefelements64,16S, 7.0, 72 and 73,are.integrally:lormed withthepindle 63. {Ihe gcasing .54' is provided fvvith..longitudinallyL spaced grooves 76, 78,80,84.and.v86and,87 extendingradally outwardly-gfromtherbore. Y*

.,As, previously,pointed fout, fluidlnormally circulates between the converter :11 ,and,..thel..coolerf34vvhile fthe vehicle is .in .,operation. When` .retardation is. desired, .this iluid circulation,` is .interrupted'byQthe valve. 48 lvv'hen 'the plunger 62 -isv moved to .the "lP position. The plunger y6@ may beheld'in Vthe "."ll' positionfora prede- .'termined, period .of 'time to obtain a viiiderange of brakling. fter-VV the ddesired "degree of. 4till is completed, the ,plungerZis released to`the",liold.positionlin vvhichthe flidflowsdn a closed loop circuitbetweenthe'retarder "44 and "theco'ler"3'4. WWheu retarfdation'is.no longer "desired,'theplunger '62 is released '.tothe release posi- `tion. When theplunger i52`is in the"release position, fthe retarder'44lis emptied-by 'the pumping action of the impller, this .etrecting a low pressure condition in the 3 `retarder which .facilitates filling when the plunger "62 is againmove'd to ll position. The positioning ofthe plungen'z in eitherthe till vor 'the""ho1dposition,is Ndetermined -by a` detent assembly 89 described hereinfterinidetail fThe' plunger 62 isillustratedin the"""hold` position in tivln'ch"retardation of lthe'vehicleoccurs. L'In that position "fluidcommunication is afforded between the retarder-"44 fthe'co'oler 34- by.` meansof aconduit' 88 extending betweenfthetreta'rder 44 and thejgro'ove 86, ithe bore "5 6, "the groove` 84, a 'conduit y"90 extending Lbetween lthe groove 584 fand"thecooler 34, a"con'duit" 92 extending between the-cooler`-34"and" thejgroove '76,'thergroove 76, the b'o1'e"-'56,` thegroove A784 and'aconduit' "94' extending between" the groove 7 8 and the retarder 444. The control landsf`68, '70 and 72, incooperati'onwth thebase 64, thusfform-a closed loop systemorfuid driven' by the fimpeller fzfothefretarder 44` throu-ghl'the "cooler34'and 'back-tothe retarder. "'The'detentfassembly89 inclu'des laiirsthelical-spring 91 arid-asecond'i'hlicalwspringf idisposed'- concentrically with respect tofthe4 helical' `spring T91. 'f-The helical'spring 93 istoflessdiameter than'ithe yspring 91 and is disposed in surrounding relation'to'a 13111395 mounted in the-end cap""61= in"aibore"`97"'which -is deiined y'at --one L'end by a t' substantially"`frustoconic`al fish'oiilder 99' against which abutsone endet `each of the 'gsprmgs 91 and v93. "Ilheoppositeend' of the spring9l1 'engages an l annular plate L 101`I which Ais normally'urged zfintofabutment with the-confronting 'faceof the annular f-plate'f58-, the annular plate 101 being receivedv inacounter bore l*103* Aand being 'movable by base section 73 iagainst :ftheforeejiof'v thev spring`91-when thesplunger "62 is'iin g" -ll= position. IThe opposite -end` of the spring 93 is receive'd lin Vabore 105 in the 'adjacent sideo the'base `N'section 73. -`It Willithus 'beiseenthatboth ofthespring lfand the f spring; 93i'areI compressed when .the plunger A"62 -is in" fill position, the' bottoming ofL the plate. '10i1 againstrthe adjacent surfacelofthe'pl.ate58fprovides a *detent"for kthe "hold.position" and (the spring'f93 is arcapable ofrbiasing plungefGZ to V'the o jpo'sition -in vvvhichreecommunication'is aiorded ,between `.the confverter11 andithe cooler 34. 'When :the valve 481is in the"o' position, as vvill .be.understood,` the retarder 44.is. evacuated by thepum-ping action of thelimpeller-SZ. ;,InLopeatiom,theplungen62-.is manually moved.-to1he llf position. In this position the base section 73 moves the plate 101 to its terminal position in which the spring 91 is fully compressed. The control lands 68, 70 and 72 are moved simultaneously to positions in which uid may iiow from the converter 11 to-the retarder 44 by means of conduit 32, groove S0, bore 56, groove 78, and conduit 94. This uid is continuously cooled by circulating from the retarder 44 to the cooler 34 by means of the conduit 88,ithe groove '*86, k`'thefbore56ra`nd" the conduit l0 90. fFlow-.is .then-.affordedifromtthevcooler-:34 by vvvay of,:conduit92, the; groove 176,3thef-boref56jthe groove-78, and the conduit 94 to the retarder. As pointed out previously, theplungerfz'may"beiheld'in""ll' position for a predetermined-period tot time oi retardation, within 15 limits of course. `It will be apparent that the entire amount of uid utilized for retardation is subject to the cooling action at all times during retardation when the plunger-.62;is-in -.holdf,position.

When retardation-is-nodonger required, the,plunger.62 is-.released by ,the-operator r and isimoved tozaninoperative position by means of spring 93. In this oilposi- Vtioniiuid liows from the` eonverten f11to.the cooler-34 by means ofztheV conduitrSZ, ithe,Y groove-80, .the bore- 56,rthe :groove f84 fand the conduit-390. ltiscontemplatedtthat .the iluidbe-,transmitted.to. the .coolen 34rat-sa v pressure .of approximately l45, ,-p.s.. and be :discharged .therefrom at -apressure:oflppproxmately 5 p.s.i.ftofbeitransmitted to `the sump18 by means ofthe conduit 36. .'*Itvwill-be noted 0 .the lhydraulic :transmission -upstreamr offthe pressure reg- -ulating Ivalve '401-Whiehcontrols the ruid pressure-toI approximately l0;p;s.i. lIn order.` toi prevent backing 1up #of the fluid'.` torthe-oiLcoolerf while the 'plunger-:62 .fis `.inthe fhold `positions-a v checkvalve :109 is- -interposedainfthe 5 :conduit-36. #Asl-the'plunger (S21-is movedto ""of posi- .tion,-.lthefluidrin .the retarder .44 .is :discharged to the -sumpaf18 byfmeans ofthe conduit 88,. the groove-86, the

bore 56 and a conduit 111.

To facilitatethe operation ofthe detent assembly 89,

40 -the base-.section l-'fisjprovidedwitha central -bore 113 .communicating with-a radial.A passage 1-15.in'the spindle 63. The passage Y 115, vin :all positions 'of lthe plunger 62, .communicates withI ther-sump f18by-means^of the'v conduit 111,- as-willbeapparent. Thetabove described vehicle vbnalrngsystern exhibits important advantages, over fretarders heretofore -known. :For example, .the amount :of iluid iiovving*L through the cooler 34;'during iretardation--isilnot throttled in anyway. By contrastfafter-aJ predetermined gquantityfof fluid is admitted to .theclosed loop` system Iandthe plunger 62 moves to the '-lhold position, this 'fluid is-4 continuously circu- ,latedbetween .the retarder@ and the'coolerasflong asbrakfingiactionis-desired :By this:arrangement;suicientcool- `ling ispprovide'd-to dissipateall ofthe heat; generated in the retarderfzduring vehicle brakingeven .underadverse-conditions.

While lhavedescribed my invention in connection with certan -specific constructions and arrangements, -itis to be understood that this is by #Way -of illustration-and-not .'dened solelyby the-appendedv claims which should-,be -construed,.as .broadly :as ,the priorv art will-permit.

I claim:

1. =.A .y hydraulic :retarder control apparatusfcomprising `afsource .of.I fuid underpressure-.control 'means forA Are- Arinsing: thepressureofsaid fluid toa predetermined-value,

ashydrodynamic coupling, la' Lheat exchanger f adaptedv to cool the fluid, in-,saidshydrodynamic-coupling, a-Ihydro- ,idynamic.-retardercomprising :a:V rotor-and a stator,land `control :means -.-for ,selectively esequestering a tportion of r-theiiuidfofisaid hydrodynamic vcouplingintofa closedloop ,system :aording t communication -zbetweensaid retarder A\.and. said cooler.

2....In.,ahydraulic:transmissionyhavingea hydrodynamic `coupling,meansfProvidingasourceotliuichunden-pressure '-that-,theconduit communicatesfwithfthe fluidV systemfof,

to said coupling, a heat exchanger, means providing communication between said coupling and said heat exchanger, a hydrodynamic retarder adapted to be connected to a rotatable element, and control means for selectively filling said retarder from said coupling, said control means being operative to divert a portion of the uid from said coupling into a closed loop circuit including said retarder and said cooler.

3. In a hydraulic transmission having a hydrodynamic coupling, a sump, a pump for transmitting fluid under pressure from said sump to said coupling, a pressure regulator interposed between said pump and said coupling for controlling the pressure of fluid delivered to said coupling, a heat exchanger, a conduit connecting said coupling to said heat exchanger, a conduit connecting said heat exchanger to said sump whereby uid flowing from said coupling to sump is cooled, the improvement comprising a hydrodynamic retarder having a rotor Iand a stator, and control means for selectively diverting a portion of the fluid from said first-named conduit into said hydrodynamic retarder and for eifecting a closed loop circulation between said retarder and said heat exchanger.

4. In a hydraulic transmission having a hydrodynamic coupling, a sump, a pump for transmitting uid under pressure from said sump to said coupling, a pressure regulator interposed between said pump and said coupling for controlling the pressure of iluid delivered to said coupling, a heat exchanger in fluid communication with said coupling for cooling uid from said coupling, said heat exchanger being operable to discharge the fluid to said sump, the improvement comprising a hydrodynamic retarder having a rotor adapted to be connected for rotation with a rotatable element of the transmission and a stator, and control means for selectively diverting a portion of the fluid from said coupling to said retarder, said control means including a valve operative in one position to ll said retarder, in another position to effect a closed loop circulation between said retarder and said heat exchanger and in another position to aord discharging of the uid in said retarder to said sump.

5. In a hydraulic transmission having a hydrodynamic coupling, a sump, a pump for transmitting uid under pressure from said sump to said coupling, a pressure regulator interposed between said pump and said coupling for controlling the pressure of iluid delivered to said coupling, a heat exchanger in fluid communication with said coupling for cooling fluid from said coupling, said heat exchanger being operable to discharge the fiuid to said sump, the improvement comprising a hydrodynamic retarder having a rotor adapted to be connected for rotation with a rotatable element of the transmission and a stator, control means for selectively diverting a portion of the uid from said coupling to said retarder, said control means including a valve having control lands spaced in a manner to alord communication between said heat exchanger and said coupling in one position, to aford iilling of said retarder in another position and to afford discharging of iiuid from said retarder in still another position.

6. In a hydraulic transmission having a hydrodynamic coupling, a sump, a pump for transmitting fluid under pressure from said sump to said coupling, a pressure regulator interposed between said pump and said coupling for controlling the pressure of iluid delivered to said coupling, a heat exchanger in uid communication with said `coupling for cooling fluid from said coupling, said heat exchanger being operable to discharge the fluid to said sump, the improvement comprising a hydrodynamic retarder having a rotor adapted to be connected for rotation with a rotatable element of the transmission and a stator, control means for selectively diverting a portion of the iuid from said coupling to said retarder, said control means including a valve having a casing provided with a bore, a plunger slidably disposed in said bore and provided with a plurality of spaced control lands to afford fluid communication between said coupling and said heat exchanger in one position, fluid communication between said coupling, said retarder and said heat exchanger in another position and fluid communication between said heat exchanger and said retarder in still another position, and a detent assembly for indexing the several positions of said valve plunger.

7. In a hydraulic transmission, a hydrodynamic coupling, a fluid circuit for supplying fluid under pressure to said coupling, a heat exchanger in said fluid circuit for cooling the fluid, a hydraulic retarder having a rotor and a stator, said rotor being adapted to be connected to a rotatable element, and means for selectively providing uid communication between said circuit and said retarder and sequestering a portion of the fluid from said circuit in a closed fluid circuit including said retarder and said heat exchanger so that the kineticenergy of the rotatable element is converted to heat.

8. In a hydraulic transmission, a hydrodynamic coupling, a iluid circuit for supplying Huid under pressure to said coupling, a heat exchanger in said liuid circuit for cooling the iluid, a hydraulic retarder having a rotor and a stator, said rotor being adapted to be connected to a rotatable element, and a valve for selectively providing uid communication between said circuit and said retarder and sequestering a portion of the fluid from said circuit in a closed fluid circuit including said retarder and said heat exchanger so that the kinetic energy of the rotatable element is converted to heat, said valve having a casing formed with a bore, a plunger slidably mounted in said bore, means for indexing said plunger to a plurality of nite positions, said plunger having a plurality of lands in sliding engagement with the wall dening said bore, said casing being formed with a plurality of axially spaced annular grooves communicating with said bore, means aiording fluid communication through certain of said grooves between said coupling and said heat exchanger in one position, between said coupling, said retarder and said heat exchanger in another position and between said retarder and said heat exchanger in a closed loop circuit in still another position.

9. In a fluid pressure system for automotive vehicles, a pump, a source of fluid, said pump being operable to transmit iluid under pressure from said uid source to a point of utilization, said fluid being adapted to return to said fluid source thus forming a closed fluid circuit, a heat exchanger in said uid circuit for cooling the fluid, a hydraulic retarder having a stator and a rotor adapted to be connected to a rotatable element of the vehicle, and means for selectively diverting a portion of the iluid to ilow in a second uid circuit including said heat exchanger and said retarder, said means including a valve having a casing formed with a bore, a plunger slidably arranged in said bore, a plurality of axially spaced grooves formed in said casing in communication with said bore, said plunger being formed with a plurality of spaced lands, means for indexing said plunger to a plurality of linite positions to restrict the ilow of iluid to said iirst iluid circuit in one position and restrict the ow of iluid to said second circuit in another position.

10. A control valve for a fluid pressure system including a rst uid circuit having a source of iluid, a pump for transmitting iiuid under pressure to a point of utilization in which heat is developed, a heat exchanger for removing the heat from the iluid, a hydraulic retarder, said control valve being operative in one position to feed uid under pressure from said first circuit into a second circuit including said retarder for said heat exchanger, operative in another position to sequester a portion of the uid in said second circuit and operative in another position to afford the release of fluid from said second circuit to said iirst circuit.

. l1. In a hydraulic transmission, a hydrodynamic coupling, a fluid circuit for supplying uid under pressure to said coupling a heat exchanger in said fluid circuit for 'FZ7 cooling the uid, a hydraulic retarder=having` al rotor -and -a-stacor, saidrotor -beingadaptedvtobe connected to-a Huid communication x-b'e'tvveen sid'ic's-irci1it `-andvisaid- "re tarder andsequestering-a portion'lof theuidffrcini'f-sid circuit-inf a `closed-'fiuid ycircuit including rsa-icll retarder and saidA heat eXchangenso-that' lche -lcinetie energybf theresaidspr-ing -beingi in-abutln1ent-with vashoiilder deii'nedl by a' bore in ``said casing, aA second Lhelical spring received '-withinsa-id' casingebore, nieans for maintaining ai predetermined compressionomsaid second spring; -sa'idA plunger beingVA movable e successively' from one 'position' in lwhich said rst spr'ingfis-uncompressed 'to aesecondposition 'in V8 which said rst spring is vcompressed and to a third position which both Y of said springs 'are `compressed, -said lr`-ni1nication through Pcertain-v of f said-"groovesi-betwe'en isaid coupling and said heat exchanger in said'ne' position,

"between said coupling, fsaid retarder' and said* heat'A exvsaid heac exchangerein a closed loop circuit inlsaid vsecond--position.

lRefe'r'enc'es. Cited in thel -le ofi thisf patent UNITED STATES PATENTS 2,827,989 `Chiiscenson Mar.-25, 1958 2,832,428 Kelley etwal.k v v Aprf29, 1958 V2,864,473 -Christenson.et al #Dec. 16, 1958 Mme' 

